To express certain political views. The allusion is to the custom, in Queen Annes reign, of wearing on the face little black patches. If the patch was on the right cheek, it indicated that the wearer was a Whig; if on the left cheek, that she was a Tory; if on the forehead between the eyes, or on both cheeks, that she was of no political bias. (See COURT PLASTER.)

1

Whatever might be her husbands politics, she was at liberty to patch as she pleased.Nineteenth Century, February, 1890, p. 58.